Low sulphur fuel system

ABSTRACT

IN ACCORDANCE WITH THE METHOD AND APPARATUS HEREIN SET FORTH, AN OIL FLUID COKER AND A COAL DEVOLATILIZER ARE INTERCONNECTED WITH A HEAT GENERATOR, WHEREBY TO EFFECT THE FORMATION OF A DARBONACEOUS PRODUCT OR CHAR, WHICH IS A COMBINATION OF OIL FLUID COKE AND DEVOLATILIZED COAL. BY-PRODUCTS FROM THE OIL FLUID COKER, AND FROM THE COAL DEVOLATILIZER, AND FROM THE HEAT GENERATOR MAY BE SEPARATELY WITHDRAWN. THE HEAT GENERATOR IS SECTIONALIZED TO PROVIDE FOR A MAXIMUM REMOVAL OF SULPHUR FROM THE CARBONACEOUS PRODUCT, OR FUEL, AND TO EFFECT A PARTIAL GASIFICATION THEREOF, AND TO PROVIDE FOR THE BURNING OR COMBUSTION OF THE FUEL DIRECTLY WITHIN THE HEAT GENERATOR, FOR MAXIMUM COMBUSTION EFFICIENCY.

May 22 1973 A. D. SINGH LOW SULPHUR FUEL SYSTEM Filed Dec. l0,

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United States Patent O U.S. Cl. 201-17 14 Claims ABSTRACT F THEDISCLOSURE In accordance with the method and apparatus herein set forth,an oil fluid coker and a coal devolatilizer are interconnected with aheat generator, whereby to effect the formation of a carbonaceousproduct or char, which is a combination of oil fluid coke anddevolatilized coal. By-products from the oil fluid coker, and from thecoal devolatilizer, and from the heat generator may be separatelywithdrawn. The heat generator is sectionalized to provide for a maximumremoval of sulphur from the carbonaceous product, or fuel, and to effecta partial gasification thereof, and to provide for the burning orcombustion of the fuel directly within the heat generator, for maximumcombustion efficiency.

This invention relates to a process and apparatus providing a lowsulphur fuel system; and utilizes a process and apparatus of the generaltype and kind set forth in my prior Pat. No. 3,437,562, dated Apr. 8,1969, and entitled Process for Producing Combined Coal Char and OilCoke, and Co-Products Therewith. The present invention provides certainimprovements over the process and appartus set forth in my prior patent.

One important improvement provided by the present invention is theprovision of means and methods for burning the carbonaceous productformed by the combined fluid coking of oil and devolatilization of coaldirectly Within and as a part of the formation process; whereby theexpense of heat loss of separately provided combustion apparatus isavoided.

A further object of the invention is to provide, in connection with theabove, improved burning or combustion means for the carbonaceousproduct, or combined char,.

whereby to provide increased efficiency in the combustion or burning ofthe combined char fuel product.

A still further object of the invention is to provide in a process forproducing coal char and oil fluid coke, improved means for effecting areduction of sulphur in the products of combustion, by the use of areducing agent, such for example as hydrogen, embodied as a part of thefuel production system. p

A still further object of the invention is to provide in a process andapparatus of the type set forth, means for effecting a gasification ofthe fuel, in a desired degree, whereby to gasify a desired proportion ofthe end products of the system, and thereby effect a gasification of theoriginally supplied fuel, as for example the coal.

Various other objects, advantages and features of the invention will beapparant from the following description, taken in connection with theaccompanying draw- ICC ing, wherein a preferred embodiment of theinvention is set forth for purposes of illustration.

Referring more specifically to the drawing:

FIG. l sets forth a diagrammatic View of the disclosed embodiment, and

FIG. 2 is an enlargement of a portion thereof.

There is illustrated an oil fiuid coker 10, a coal devolatilizer 12, anda heat generator 14 of the general type and kind, and in the generalarrangement set forth in my prior patent.

As in said prior patent, preheated oil under pressure, which may becrude oil, reduced crude oil, or other modified residual oil such forexample as Bunker-C or the like, is supplied from a supply line 16 to aplurality of spray nozzles 18 and 20 within the oil fluid coker, undercontrol of valves 22 and 24.

As shown, suitably granulated raw coal, together with steam, fuel gas,or other fluidizing media, is introduced into the coal devolatilizer,under pressure, from a supply line 26 under control of a valve 28.

The heat generator 14 is in certain aspects and functions similar to theheat generator of my said prior patent, but also differs materiallytherefrom. More specifically, in this instance the heat generator isprovided with an upper chamber or section 30, an intermediate chamber orsection 32, and a lower chamber or section 34. Product from the oilcoker discharged from the lower end thereof through :a conduit 36 undercontrol of a valve 38, is transmitted by preheated air under pressurefrom a supply line 40, under control of a valve 42, through a conduit 44into the upper section 30 of the heat generator. In a similar mannerproduct from the coal devolatilizer delivered from the lower end thereofthrough a conduit 46 under control of a valve 48, is delivered bypreheated air under pressure from a supply line 50 under control of ava-lve 52, through a conduit 54 also into the upper chamber 30 of theheat generator.

As shown, product is delivered from the upper generator section orchamber 30 into the intermediate chamber or section 32 by means of avalve controlled conduit 56; and similarly product is delivered from theintermediate chamber or section 32 into the lower section or chamber ofthe heat generator, through a valve controlled conduit 58. Product isalso transmitted from the upper heat generator section 30 into the oilfluid coker through a conduit 60 under control of a valve 62.

In a similar manner product from the upper chamber 30 of the heatgenerator is transmitted to the coal devolatilizer through a conduit 68under control of a valve 70, and/ or through a conduit 72 under controlof a valve 74; into the -supply conduit 26.

The operation of the parts thus far described is generally similar tothe operation in my said prior Pat. No. 3,437,562. Within the oil fluidcoker the oil -delivered thereto is subjected to a partial cracking andcoking procc ss and the coal delivered to the coal devolatilizer issubjected to devolatilization, and heat treatment, and the productstherefrom are delivered through the conduits 44 and 54 into the uppersection 30 of the heat generator. Product from the upper section 30 ofthe heat generator is in turn transmitted back to the oil fluid cokerthrough the conduit 60, and to the coal devolatilizer through theconduits 68 and/ or 72. A partial burning of the product, and thus aheat generation, is provided within the heat generator section 30, thussupplying heat to the system, within the heat generator and within theoil Huid coker and the coal devolatilizer. Through the continuousinterchange of material, as above set forth, a carbonaceous product isformed which is a combination of oil fluid coke and coal char, all asset forth with particularity in my said prior patent.

To effect a proper functioning of the system, steam is supplied as astripping medium from a supply conduit 76 to stripping heads disposedrespectively within the conduits 60 and 36, the delivery of the steam tothe stripping heads being suitably individually valve controlled. Steamis also supplied from conduit 76 to a iluidizing head 78 within thelower portion of the oil fluid coker, under control of a 'valve 80. In asimilar manner steam is supplied as a stripping medium from a supplyconduit 82 to valve controlled stripping heads individually disposedwithin the conduits 68, 72 and 46; and steam from the supply line 82 isalso supplied to a fluidizing head 84 within the lower portion of a coaldevolatilizer, under control of a valve 86.

As has been previously described, in accordance with the presentinvention the heat generator is sectionalized into an upper section orchamber 30, and an intermediate section or chamber 32. Preheated airunder pressure is supplied through a valve controlled conduit 88 intothe upper heat generator section, to a fluidizing head 90, which acts tofluidize the bed, and also supplies air to the chamber so as to effect apartial burning of the product within the chamber, as previouslydescribed. Pressure is maintained within the chamber 30, within therange from 50 p.s.i. to 1000 p.s.i., and preferably approximating thelatter, for reasons as will be presently described. This of courserequires that the entire system be operated under pressure, to permit aninterchange of the materials between the vessels. The temperature withinchamber is preferably maintained at approximately l250 F., andtemperatures within the oil fluid coker and the coal devolatilizer maybe maintained within the range of l900 F. to 1000 F.

By-products from the' oil uid coker may be collected through a dischargeconduit 92 under control of a valve 94; and from the coal devolatilizerthrough a conduit 96 under control of a valve 98; and from the uppersection of the heat generator through a conduit 100 under control of avalve 102, the by-products thus delivered, and to be recovered, being essentially similar to those discharged from the oil fluid coker, the coaldevolatilizer, and the heat generator in the apparatus and process of mysaid prior patent.

In accordance with the present invention the product within theintermediate heat generator chamber 32 is subjected to the action ofhydrogen gas, supplied thereto from a supply line 104 under control of avalve 106, leading to a iluidizing head 108 within the lower portion ofthe said intermediate chamber 32. Preferably the temperature of theproduct within the chamber 32 is maintained in the range of 1600 F. to1800 F.

Within this high temperature range hydrogen reacts very readily with thesulphur in the combined char, the resulting gases consisting essentiallyof H2S, excess H2, and some hydrocarbon gases being discharged from theintermediate chamber through an exhaust line or conduit 109 undercontrol of a valve 110.

Further, in accordance with the present invention, the exhaust productsfrom the line or conduit 109 are subjected to the action of a lime ordolomite hydrogen recovery system, generally indicated by the referencenumeral 112, from which, after treatment, at least a considerableportion of the hydrogen is recovered for recirculation to the heatgenerator section 32.

More particularly, the hydrogen recovery apparatus may comprise an upperchamber 114, within which the lime or dolomite is disposed, and to whichthe exhaust gases consisting essentially of H2S and H2 may be deliveredfrom the chamber 32, as previously set forth. The solid reactionproducts from chamber 114 of the hydrogen recovery apparatus aredelivered through a conduit 116 into a second chamber 118, beingsubjected during the transmission to the action of a heat extractor asindicated at 120. Treatment gases, such for example as CO2 and steam maybe introduced into the intermediate chamber 118, and the solid reactionproducts again transmitted by means of a conduit 122 into a furtherreaction chamber, as indicated at 124, into which fuel gas and air maybe introduced, to effect a combustion operation. From chamber 124 thethus treated lime or dolomite is delivered by means of a conduit 126 andpump 127 back into the upper chamber 114 of the recovery apparatus,being subjected during such transmission to the action of a heatextractor as indicated at 128.

In a hydrogen recovery system such as above set forth, a part of thegaseous hydrogen, along with other gases, are discharged from thechamber 114 through a conduit 130 into a gas separator, as indicated at132, from which the various gases may be individually discharged throughconduits as indicated at 134; the hydrogen being discharged through aconduit 136 under control of a valve 138. Some of the gaseous hydrogenis also discharged from chamber 118 into a gas separator 142 from whichother gases may be discharged through a conduit 144 and from whichgaseous hydrogen may be discharged through a conduit 146 controlled byvalve 148 interconnecting with the conduit 136. Conduits 136 and 146 aredirected by a fan 149 into the hydrogen supply line 104 for the chamber32 of the heat generator; and makeup hydrogen may additionally besupplied from a supply line 150 under control of a valve 152. Thereaction of hydrogen with sulphur, within chamber 32, to form hydrogensulphide (H2S) is a reversible one. By providing an excess of hydrogenan optimum removal of the sulphur may thus be obtained, and by means ofa hydrogen recovery system, as above set forth, an excess of hydrogenmay be continuously supplied without undue expense.

From chamber 32, the combined char, with a very considerable amount ofthe sulphur removed, is transmitted through conduit 58 into the lowerburning or combustion chamber 34 of the heat generator, wherein thecombined char may be burned, as fuel; and as shown in the drawing, theheat of such combustion is utilized to generate steam within a steamgenerating system, as indicated at 154. Air, to effect the combustionprocess, is introduced into the combustion chamber 34 from a supply line156, under control of a valve 158, to a fluidizing head 160, whichsupplies combustion air, and also uidizes the fuel bed within chamber34, for maximum burning efficiency.

By reason of the arrangement thus provided, it will be seen that thecombined char may be burned, as fuel, directly within the heatgenerator, thus making unnecessary the mechanical transmission of thecombined char to a remote burning location, with its incident expenseand heat loss. The transmission of the products of combustion from thechamber 34 may be effected through an exhaust line or flue 162, undercontrol of a valve 164; and such exhaust gases will have a minimum ofSO2, by reason of the sulphur elimination chamber 32, as previouslydescribed. Exhaust line or flue 162 may lead, if desired, into anysuitable secondary combustion system. Ash is discharged from thecombustion chamber 34 through an exhaust line 166, under control of avalve 168.

A further reaction may also be effected within the reaction chamber 32,between the hydrogen and the carbon of the combined char, to formmethane (CH4). AS this reaction proceeds, the combined char is in effectgasified by the hydrogen thus providing, in effect, a coal gasificationsystem. By holding the combined char within chamber 32 for longerperiods, and at higher temperatures and pressures, a greatergasification may be effected, and in this manner the amount of carbongasification in relation to the amount of combined char transmitted tothe combustion chamber 34 may be controlled, in accordance with optimumdesired conditions. Since the reaction between H2 and carbon in thel6002000 F. temperature range is highly exothermic, controlledquantities of steam may be added with the incoming hydrogen to achieveadditional sulphur removal and gasification of the carbon, while alsocontrolling the temperature of the fluidized bed in the desired range.To this end a valve 170, suitably remotely controlled, may be providedin the transmission line S8 between the chambers 32 and 34.

Cyclone dedusters (not shown) are preferably installed in the gas outletlines leading from the oil fluid coker, the coal devolatilizer, and theheat generator; and from the vessels 114, 1118 and 124 of the H2recovery system, to effect solid material separation and thusinadvertent withdrawal of solid matter with the gas from the system.

It will be seen that in accordance with the lime or dolomite hydrogenrecovery system herein provided, there is a mixing of the dolomite orlime only with the HZS gas from which the hydrogen is to be recovered.The linvention thus eliminates the mixing of dolomite or lime with coalchar or combined char, with its incident difiiculties and the incidentseparat-ion steps which would thus be required.

It will be seen that the invention thus provides, in a system forproducing combined char from coal and oil, for the direct burning of thecombined char, or carbonaceous product, within the heat generator withinwhich the product is formed, for maximum combustion efficiency. Means isfurther provided for maximum removal of sulphur from the fuel, beforeburning; and means is still further providing for effecting agasification of the fuel, in a desired percentage, as a part of the fuelproduction system.

The invention is claimed as follows:

1. The method of treating coal and oil which comprises, separatelysubjecting coal in a first treatment zone to the action of heat todevolatilize the coal and produce a coal char, separately subjecting oilin a second treatment zone to the action of heat to crack the oil andproduce a fluid coke, mixing the char and fluid coke while subjected tothe action of heat to provide a carbonaceous product the individualparticles of which comprise combined coal char and oil fluid coke,recirculating the mix directly into said first and second treatmentzones, and subjecting the carbonaceous product while heated to theaction of hydrogen to react with the sulphur therein to reduce thesulphur content of the carbonaceous product.

2. The method of treating coal and oil as defined in claim 1, whereinthe hydrogen is applied to the carbonaceous product under heat and highpressure.

3. The method of treating coal and oil as defined in claim 1, whereinthe hydrogen is recirculated in a continuous cycle into contaci with thecarbonaceous product.

4. The method of treating coal and oil which comprises, separatelysubjecting coal in a first treatment zone to the action of heat todevolatilize the coal and produce a coal char, separately subjecting oilin a second treatment zone to the action of heat to crack the oil andproduce a fluid coke, mixing the char and fluid coke while subjected tothe action of heat to provide a carbonaceous product the individualparticles of which comprise combined coal char and oil fiuid coke,recirculating the mix directly into said first and second treatmentzones, and subjecting the carbonaceous product while heated to theaction of hydrogen to react with the sulphur therein to reduce thesulphur content of the carbonaceous product.

5. The method of treating coal and oil as defined in claim 4, whereinthe hydrogen is applied to the carbonaceous product under heat andpressure.

6. The method of treating coal and oil as defined in claim 4, whereinthe hydrogen is recirculated in a continuous cycle into contact with thecarbonaceous product.

7. The method of treating coal and oil which comprises, separatelysubjecting coal in a first treatment zone to the action of heat todevolatilize the coal and produce a coal char, separately subjecting oilin a second treatment zone to the action of heat to crack the oil andproduce a fluid coke, mixing the char and fluid coke while subjected tothe action of heat to provide a carbonaceous product the individualparticles of which comprise combined coal char and oil fluid coke,recirculating the mix directly into said first and second treatmentzones, and iburning the carbonaceous product while it retains itssensible heat.

8. The method of treating coal and oil as defined in claim 7, whereinthe burning of the carbonaceous product is effected under pressure.

9. Apparatus for treating coal and oil comprising, a coal devolatilizerdefining a first chamber within which coal is subjected to the action ofheat to devolatilize the coal, and oil fluid coker defining a secondchamber within which oil is subjected to the action of heat to crack theoil and produce a fiuid coke, a heat generator defining a third chamberwithin which the devolatilized coal and oil fluid coke are mixed andreacted in the presence of air to generate heat and form a carbonaceousproduct the individual particles of which comprise combined coal charand oil fiuid coke, means for recirculating the devolatilized coal andoil fluid coke between said first, second, and third chambers, and meansfor supplying hydrogen to the heat generator.

10. Apparatus as defined in claim 9, wherein said coal devolatilizer,said oil fluid coker and said heat generator are maintained underpressure.

11. Apparatus for treating coal and oil comprising, a coal devolatilizerdefining a first chamber within which coal is subjected to the action ofheat to devolatilize the coal, an oil fluid coker defining a secondchamber within which oil is subjected to the action of heat to crack theoil and produce a fluid coke, and a heat generator defining a thirdchamber within which the devolatilized coal and oil fluid coke are mixedand reacted in the presence of air to generate heat and form acarbonaceous product the individual particles of which comprise combinedcoal char and oil fiuid coke, said heat generator chamber beingsectionalized with the sections in cornmunication to subject thecarbonaceous product therein to sequential processing steps, one sectionof said heat generator chamber being provided with means to supplyhydrogen to the carbonaceous product therein.

12. Apparatus for treating coal and oil as defineddn claim 11, whereinone section of said heat generator is provided with means to effect theburning of the carbonaceous product therein.

13. The method of treating coal and oil as defined in claim 1, whereinsteam is applied to the carbonaceous product with the hydrogen', and thehydrogen is recovered by subjecting the hydrogen sulphide formed to theaction of a hydrogen separating agent such as dolomite or lime.

l14. Apparatus for treating coal and oil comprising, a coaldevolatilizer defining'a first chamber within which coal is subjected tothe action of heat to devolatilize the coal, an oil fluid coker defininga second chamber within which oil is subjected to the action of heat tocrack the oil and produce a fluid coke, and a heat generator defining athird chamber within which the devolatilized coal and oil fluid coke aremixed and reacted in the presence of air to generate heat and form acarbonaceous product the individual particles of which comprise combinedcoal char and oil fiuid coke, means for recirculating the dcvolatilizedcoal and oil fluid coke between said first, second, and third chambers,and means within the heat generator for burning the carbonaceous producttherein.

References Cited (Other references on following page) 7 UNITED STATESPATENTS 8 OTHER REFERENCES Minet 201-31 Ser. No. 801,460, February 1969,Singh, copending Feldkirchner et al. 48-197 application. Gorin et al.201-17 Aspegren 201-28 X 5 NORMAN YUDKOFF, Primary Examiner Smith201--28 X D. ED ARD Wennsky 201 28 W S Asslstant Examiner Welinsky2101-28 U S CL XR. S' h 201--23 im et aL 1 17 10 zel- 23, 26, 31, 33;2oz- 114; 48-197 R, 101 Nelson et a1. 201-17

